Flame Photometer Sherwood Na with K

Flame Photometer Sherwood - 425

  • Now with Calcium which can be measured with Na and K
  • Enhanced software improving accuracy and reducing errors
  • Fully interactive with New Model 860 Autosampler

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    Why buy from Geneq? - find out more

    Ever since the revolutionary Model 420 was introduced we have been asked to add calcium measurement.

    This has been accomplished without any reduction in the existing capability of the Model 420, due in part to the very well-established aspiration, sample mixing, and burner configuration of the original Model 410 system. The stable flame allows very efficient dispersion and thermal dissociation of the sample compounds leading to a reproducible emission of the elements under analysis.

    The Model 425 Flame Photometer (475 42 500) expands upon the capability of the Model 420 Flame Photometer with the addition of a detector and filter assembly specific for Calcium determination.  It also offers a “301 mode” feature which allows connection to a few of the more popular continuous flow systems.

    The Model 425 defaults to measurement with Lithium Internal Reference. This should be added to the blank, calibration standards and samples such that they all contain the same concentration of Lithium; i.e. ~ 100 ppm.  The Model 425 is supplied with Li solution 001 56 622. This should be diluted 1:10 with distilled water and the resulting solution used as the blank to dilute the calibration standard and samples.  Sherwood Scientific can supply a 3 Molar solution of Li (001 56 603; 6x 100 ml) which when diluted 1:200 will give the optimum Lithium internal reference level. This is cheaper than using the 001 56 622 and is designed to be used with the Model 805 Dilutor where it is simultaneously diluted and mixed to the correct dilution for blank, calibrators and samples.

    The Model 425 Flame Photometer has RS232 output for printer or computer connection and is compatible with our Model 860 Autosampler for unattended sample analysis. The Model 425 may be used with the Model 805 Continuous Flow Dilution, again in conjunction with or without the Model 860 Autosampler and with or without BlueNotes 420 software

    A new optical arrangement implemented in 2018 gives improvement for the hitherto known issue of Sodium interference with Calcium determinations.  Previously reported interference was around the 4% mark and interference in newly manufactured units is now reduced to be less than 1% for samples containing equal concentrations of both Sodium and Calcium.


  • Now with Calcium which can be measured with Na and K
  • Enhanced software improving accuracy and reducing errors
  • Fully interactive with New Model 860 Autosampler
  • Another Now Flame Photometer from the Experts
  • On-board firmware with blanking, calibration, and sample routines.
  • Simultaneous measurement of two of four elements: Sodium, Potassium, Calcium and/or Lithium.
  • Linearised Sodium response over the Sodium concentration range 0.5 to 20 ppm
  • Internal Reference facility (Lithium) for improved precision.
  • Automatic flame ignition and optimization.
  • Safety features include optical flame and low air pressure detection for fuel gas shut-off.
  • Two digital displays for calibration and analysis data of each channel; analog outputs for use with chart recorders and some online analyzers.
  • A “no tools” maintenance approach allows easy access to the mixing chamber and burner assembly.
  • RS232 for data output to a serial print

  • Automation

    The New Model 860 Autosampler fits entirely within the dimensions of the Model 805 Diluter giving the smallest footprint available. The Model 860 Autosampler is integrated with the Model 425 operating system with a bi-directional connection. The operation couldn’t be simpler. Pressing the Blank and Calibrate buttons on the Model 425 sends the Model 860 probe to the blank and calibrant vessels on board the Autosampler carousel. The system, after calibration, is ready for the run to begin. Press Measure and walk away! The Model 860 automatically detects the last sample and finishes the run.


    Na with K

    • Essential clinical elements for electrolyte balance
    • Animal metabolic testing in Pharma companies
    • QC of Infusion fl uids


    • Biological samples (with pre-treatment)
    • Food Samples

    Ca with Na

    • QC in Paper Mills
    • Cement

    Ca with K

    • Plant studies
    • Soil Testing
    • Fruit juices

      Measurement Range into Flame0-40 ppm0-20 ppm0-100 ppm0-100 ppm
      Display range0-199.90-199.90-199.90-199.9
      Sensitivity to show 100 units0.5 ppm0.5 ppm2.0 ppm5.0 ppm
      Detection Limit20 ppb20ppb50 ppb0.50 ppm
      Specificity< 0.5% interference from an element at the same concentration of the element under analysis
      Linearity± 1 % at 50% of the displayed value
      Model 860 Autosampler
      Samples Measured40 x 2 ml
      Volume required200 µl
      Blank and Standard10 ml on board
      System Speed> 60 per hour for two channels